@MFrampton -- Eh, actors are always playing characters younger than they are. Jason Behr was 29 or 30 when he was cast as a 16-year-old for the show Roswell back in the day. Kristen Bell was in her 20s when she played 17 yo Veronica Mars. Etc. etc. Looking young is the key. I think this guy will be fine. Four is 18, I believe, so a year or two older than Tris.